1. Field of the Invention
The invention relates to new compositions containing compounds having cyclic isourea groups in combination with organic polycarboxylic acids.
2. Description of the Prior Art
One-container, two-component systems are known. These are understood to include lacquer binders consisting of two individual components which only react with one another, in a crosslinking reaction, at elevated temperature and can therefore be combined and stored in one container at room temperature. The best-known coating compositions of this type include combinations of organic polyhydroxyl compounds with blocked polyisocyanates. The disadvantage of these systems is that, when the coating is stoved, the blocking agent is reformed and released into the environment.
The present invention provides novel one container, two-component coatings binders which are storable at room temperature and crosslinkable at elevated temperature without cleavage of the blocking agents. The individual components of the binders are selected from cyclic isoureas and polycarboxylic acids which are described in greater detail hereinafter.
It could not be anticipated that the mixtures according to the invention would be storage stable at room temperature, since it has previously been described in the literature that the reaction of isoureas with carboxylic acids takes place at room temperature (Chem. Ber. 100, (1967), pages 16 to 22).
Although Japanese patent application, publication number JA 91/157 421 has previously described heat-curable compositions containing cyclic isoureas, these are ternary mixtures which, in addition to the isoureas, contain polyepoxides and also H-active compounds such as carboxylic acids or isocyanates.